1. Technical Field
The present invention relates to an image sensor module package structure with a supporting element, and more particularly to an image sensor module package structure whose production yield is improved.
2. Description of Related Art
With the invention and popularization of various digital image products, a market demand for image sensor modules for being applied to these digital image products, such as digital cameras, camera phones, video phones, fingerprint readers, and so on, have been gradually increased. Generally speaking, image sensor modules, while using different light-sensing elements, can be classified into complementary metal oxide semiconductor (CMOS) image sensor modules and charge couple image sensor modules.
Since the CMOS image sensor modules and the charge couple image sensor modules possess both advantages and disadvantages, respectively, they may be adopted in diverse applications according to the manufacturers' needs. However, in view of the trend of burgeoning and miniaturized digital image products, it is necessary to reduce the volumes and improve the production yield of the image sensor modules so as to meet the practical needs of modern applications.
For example, Taiwan Patent Application No. 200709444 provides a package structure for a light-sensing element. The package structure includes the light-sensing element, a base and a transparent layer. The light-sensing element is electrically connected to metallization traces on the base by a wiring means. Furthermore, by changing positions of the metallization traces, joints between metal wires and the metallization traces can be positioned at a position slight higher than a top of the light-sensing element so as to shorten a wiring distance of the metal wires and in turn reduce a package area.
In the process of manufacturing the conventional light-sensing elements, the entire transparent layer is covered on a top surface of a base of a wafer and then the light-sensing elements are cut off the wafer. Since it is difficult to ensure the absolute clearness of the transparent layer before it is put on the top surface of the base, any defect or stain on the transparent layer can jeopardize the image-sensing sensitivity and the production yield of the resultant light-sensing elements. On the other hand, in an alternative case, when a light-pervious glass is implemented as the transparent layer, edges thereof tend to be cracked or jagged in a cutting process and thus the production yield of the resultant light-sensing elements is suffered.
In U.S. Pat. No. 7,297,918, where an image sensor package structure and an image sensing module are disclosed, the image sensor package structure comprises a substrate, an image sensing chip, a light transparent layer, and a frame. The substrate has a plurality of metallization traces on a surface thereof. The image sensing chip is mounted on said substrate and electrically connected to said metallization traces on said substrate. The light transparent layer is located above said image sensing chip. The frame is mounted on said substrate and around said image sensing chip. A top of said frame extends toward said image sensing chip and upwards to form a locking and placing portion with an L-shaped cross section so that bend positions of said locking and placing portion form a placement space to accommodate and position said light transparent layer.
Though U.S. Pat. No. 7,297,918 is advantageous for having a simple structure, facilitating adhering as well as packaging, and ensuring the production yield of the image sensor module package structure by providing the locking and placing portion to prevent the light transparent layer to be cut directly, the substrate is still necessary for carrying the chip and a wiring procedure is still necessary for electrically connecting the image sensing chip and the metallization traces on the substrate. Consequently, a wiring space cannot be saved on the conventional image sensor module package structure and thus the image sensor module package structure cannot be further downsized.
FIG. 1 is a sectional view of a conventional image sensor module package structure 10. Therein, a light transparent layer 11 is combined with a chip 13 by an adhesive layer 12. The chip 13 has a plurality of light-sensing elements 14, a plurality of conducting pads 15 and at least one conducting channel 16. The light-sensing elements 14 are arranged on a light-sensing area of a top surface of the chip 13. The conducting pads 15 are electrically connected to the light-sensing elements 14 and electrically connected to one end of the conducting channel 16 passing through the chip 13. By using the chip 13 having the conducting channel 16, the image sensing chip 13 can be electrically connected to metallization traces on a substrate without a wiring procedure. As a result, the wire space can be spared in the image sensor module package structure 10 and thereby an overall volume of the image sensor module package structure 10 can be reduced.
However, because the light transparent layer 11 and the chip 13 are combined simply by the adhesive layer 12 sandwiched therebeteween, the light transparent layer 11 and the light-sensing elements 14 are distant from each other for merely a minute distance that tends to incur aberration of images, and the light-sensing elements 14 may fail to accurately sense images. Besides, if defects or stains exist on the light transparent layer 11, such defects or stains will be magnified directly and make the image sensor module package structure 10 handicapped in accurately and sensitively sensing images.